Dynamic selection of multicarrier mode based on QoS parameters

ABSTRACT

In one aspect, a transmitter, for a first time interval, allocates first and second portions of a frequency band to first and second multicarrier modulation schemes with first and second subcarrier spacings that differ from one another. The data is transmitted to wireless devices in the first time interval using the first and second multicarrier modulation schemes in the first and second portions of the frequency band. For a second time interval, third and fourth non-overlapping portions of a frequency band are allocated to third and fourth multicarrier modulation schemes that have third and fourth subcarrier spacings that differ from one another. The third and fourth portions and/or schemes differ from the first and second portions and/or schemes. The data is transmitted in the second time interval using the third and fourth multicarrier modulation schemes in the third and fourth portions of the frequency band.

TECHNICAL FIELD

The present invention generally relates to wireless communicationnetworks, and particularly relates to multicarrier modulation anddemodulation.

BACKGROUND

The so-called Long Term Evolution (LTE) wireless communication networksdeveloped by members of the 3rd-Generation Partnership Project (3GPP)use orthogonal frequency-division multiplexing (OFDM) in the downlinkand Discrete Fourier Transform spread (DFT-spread) OFDM (also referredto as single-carrier frequency-division multiple access, or SC-FDMA) inthe uplink. The basic LTE downlink physical resource can thus be seen asa time-frequency grid as illustrated in FIG. 1, where each resourceelement corresponds to one OFDM subcarrier during one OFDM symbolinterval. The uplink subframe has the same subcarrier spacing as thedownlink and the same number of SC-FDMA symbols in the time domain asOFDM symbols in the downlink.

In the time domain, LTE downlink transmissions are organized into radioframes of 10 ms, each radio frame consisting of ten equally-sizedsubframes of length Tsubframe=1 ms, as shown in FIG. 2. For normalcyclic prefix, one subframe consists of 14 OFDM symbols. The duration ofeach symbol is approximately 71.4 μs.

Furthermore, the resource allocation in LTE is typically described interms of resource blocks, where a resource block corresponds to one slot(0.5 ms) in the time domain and 12 contiguous subcarriers in thefrequency domain. A pair of two adjacent resource blocks in timedirection (1.0 ms) is known as a resource block pair. Resource blocksare numbered in the frequency domain, starting with 0 from one end ofthe system bandwidth.

Downlink transmissions are dynamically scheduled: in each subframe thebase station transmits control information about which terminals data istransmitted to and upon which resource blocks the data is transmitted,in the current downlink subframe. This control signaling is typicallytransmitted in the first 1, 2, 3 or 4 OFDM symbols in each subframe, andthe number n=1, 2, 3 or 4 is known as the Control Format Indicator(CFI). The downlink subframe also contains common reference symbols,which are known to the receiver and used for coherent demodulation ofthe control information. A downlink system with CFI=3 OFDM symbols ascontrol is illustrated in FIG. 3. The reference symbols shown in FIG. 3are the cell-specific reference symbols (CRS) and are used to supportmultiple functions including fine time and frequency synchronization andchannel estimation for certain transmission modes.

While the development and deployment of LTE networks provides users withgreatly increased wireless data rates and has enabled the development ofa wide variety of mobile broadband (MBB) services, demand for theseservices continues to grow. In addition to this increased demand forimproved bandwidth and performance, new applications for special-purposedevices, such as machine-to-machine (M2M) devices in machine typecommunications (MTC), continue to be developed. These market forcesindicate that a wireless communications technology with improvedflexibility is needed, to better match the variety of servicerequirements for mobile data applications.

SUMMARY

Narrow and wider subcarriers favor different types of services. Thecurrent LTE standard uses fixed subcarrier spacing and, therefore, isless flexible when it comes to satisfying highly varyingQuality-of-service (QoS) requirements. This is particularly true withrespect to time-critical services. A new physical layer design, whichmay be employed as a next generation or “5G” radio access technology(RAT), uses smaller and variable sized subframes with its mixed modeoperation, but it is recognized herein that there is a need for methodsand apparatus for utilizing the scalability defined for the new RAT in adynamic way for adapting to current QoS needs. The embodiments describedherein provide apparatuses and methods for selecting and (re)configuringsubcarriers based on the required QoS metrics. This may include, forexample, schemes for selection of different subcarrier configurationsand adapting them based on the required QoS demands. The configurationparameters can include subcarrier and symbol lengths in the new RAT.

The described embodiments provide dynamic operations to efficientlysupport different services. In an example, a base station decides,depending upon the type of scheduling request (SR), whether or not toallocate a dedicated resource. For instance, an emergency alarm withvery short data size could directly be sent on a control channel insteadof exercising the classical mechanism of first sending a SR.

In another example, either the base station or the device terminaldecides, depending upon the service class and/or device capability,which type of OFDM subcarrier spacing has to be allocated to fulfill theQoS requirements.

In a further example, the base station decides, which of the allocatedresources has to be freed and reallocated (when possible) in order tosupport emergent new real time traffic, considering the number ofresources and device capability constraints to ensure that the QoSexpectations are met. The reallocation of resources can use an entirelynew multicarrier (i.e., OFDM, filter bank multicarrier (FBMC), etc.)numerology, compared to the numerology for the previous allocation.

In another example, a subset of system bandwidth is dynamically (on asub frame basis) allocated to different sub-carrier spacing depending onthe current QoS needs.

According to some embodiments, a method includes, for a first timeinterval, allocating first and second non-overlapping portions of afrequency band to first and second multicarrier modulation schemes,respectively. The first and second multicarrier modulation schemes havefirst and second subcarrier spacings, respectively, and the first andsecond subcarrier spacings differ from one another. The method mayinclude transmitting data to one or more wireless devices in the firsttime interval, using the first and second multicarrier modulationschemes in the first and second portions of the frequency band. Themethod further includes, for a second time interval, allocating thirdand fourth non-overlapping portions of a frequency band to third andfourth multicarrier modulation schemes, respectively. The third andfourth multicarrier modulation schemes have third and fourth subcarrierspacings, respectively, and the third and fourth subcarrier spacingsdiffer from one another. The third and fourth portions differ from thefirst and second portions or the third and fourth multicarriermodulation schemes differ from the first and second multicarriermodulation schemes, or both. The method may also include transmittingdata to one or more wireless devices in the second time interval, usingthe third and fourth multicarrier modulation schemes in the third andfourth portions of the frequency band.

According to some embodiments, a method includes, in a first timeinterval, receiving and demodulating data from a first portion of afrequency band, using a first multicarrier modulating scheme having afirst subcarrier spacing. The method further includes, in a second timeinterval, receiving and demodulating data from a second portion of thefrequency band, using a second multicarrier modulating scheme having asecond subcarrier spacing. The first subcarrier spacing differs from thesecond subcarrier spacing.

According to some embodiments, a wireless transmitter includes atransceiver configured to transmit and receive wireless transmissionsaccording to multicarrier modulation schemes, and a processing circuitoperatively connected to the transceiver. The processing circuit isconfigured to, for a first time interval, allocate first and secondnon-overlapping portions of a frequency band to first and secondmulticarrier modulation schemes, respectively. The first and secondmulticarrier modulation schemes have first and second subcarrierspacings, respectively, and the first and second subcarrier spacingsdiffer from one another. The processing circuit may also be configuredto transmit data, via the transceiver, to one or more wireless devicesin the first time interval, using the first and second multicarriermodulation schemes in the first and second portions of the frequencyband. The processing circuit is configured to, for a second timeinterval, allocate third and fourth non-overlapping portions of afrequency band to third and fourth multicarrier modulation schemes,respectively. The third and fourth multicarrier modulation schemes havethird and fourth subcarrier spacings, respectively, and the third andfourth subcarrier spacings differ from one another. The third and fourthportions differ from the first and second portions or the third andfourth multicarrier modulation schemes differ from the first and secondmulticarrier modulation schemes, or both. The processing circuit mayalso be configured to transmit data, via the transceiver, to one or morewireless devices in the second time interval, using the third and fourthmulticarrier modulation schemes in the third and fourth portions of thefrequency band.

According to some embodiments, a wireless receiver includes atransceiver configured to transmit and receive wireless transmissionsaccording to multicarrier modulation schemes, and a processing circuitoperatively connected to the transceiver. The processing circuit isconfigured to, in a first time interval, receive and demodulate datafrom a first portion of a frequency band, using a first multicarriermodulating scheme having a first subcarrier spacing. The processingcircuit is also configured to, in a second time interval, receive anddemodulate data from a second portion of the frequency band, using asecond multicarrier modulating scheme having a second subcarrierspacing. The first subcarrier spacing differs from the second subcarrierspacing.

Of course, the present invention is not limited to the above featuresand advantages. Those of ordinary skill in the art will recognizeadditional features and advantages upon reading the following detaileddescription, and upon viewing the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a diagram illustrating an LTE downlink physicalresource.

FIG. 2 illustrates a diagram of an LTE time-domain structure.

FIG. 3 illustrates a diagram of a downlink subframe.

FIG. 4 illustrates multi-mode configurations, according to someembodiments.

FIG. 5 illustrates a block diagram of a network access node, accordingto some embodiments.

FIG. 6 illustrates a block diagram of an OFDM modulation scheme that canbe used in some embodiments.

FIG. 7 illustrates a block diagram of an OFDM demodulation scheme thatcan be used in some embodiments.

FIG. 8 illustrates a block diagram of a DFTS-OFDM modulation scheme thatcan be used in some embodiments.

FIG. 9 illustrates a block diagram of a DFTS-OFDM demodulation schemethat can be used in some embodiments.

FIG. 10 illustrates signal generation using multiple IFFT modulationschemes in each time interval, according to some embodiments.

FIG. 11 illustrates a method in a transmitter node for multicarriermodulation, according to some embodiments.

FIG. 12 illustrates a method in a receiver node for multicarrierdemodulation, according to some embodiments.

FIG. 13 illustrates a block diagram of a user equipment, according tosome embodiments.

FIG. 14 illustrates an example signal diagram for a time interval,according to some embodiments.

FIG. 15 illustrates an example signal diagram of mixed mode OFDM forconsecutive time intervals, according to some embodiments.

FIG. 16 illustrates an example signal diagram of mixed mode OFDM forconsecutive time intervals, according to some embodiments.

FIG. 17 illustrates an example signal diagram for a time interval,according to some embodiments.

FIG. 18 illustrates a functional implementation of a network access nodeoperating as a transmitter node, according to some embodiments.

FIG. 19 illustrates a functional implementation of a network access nodeoperating as a receiver node, according to some embodiments.

FIG. 20 illustrates a functional implementation of a user equipmentoperating as a transmitter node, according to some embodiments.

FIG. 21 illustrates a functional implementation of a user equipmentoperating as a receiver node, according to some embodiments.

DETAILED DESCRIPTION

There has been fast growth in the number of wireless devices andapplications in recent years, and this trend is likely to continue inthe future. With the emergence of new applications with highly varyingapplication needs, i.e., quality of service (QoS) parameters anddeployment scenarios, a single, inflexible, physical-layer technology isnot adequate to achieve the desired performance characteristics. In thiscontext, a highly flexible physical layer for a future generation ofcellular networks is currently being designed. This new physical layerdesign is geared towards fulfilling a wide range of varying QoSrequirements including latency, reliability and throughput. Thescalability is proposed to be adapted using different subcarrierspacing. Another feature proposed for this new physical layer is that itshould support mixed mode operation, which allows different subcarrierspacings to simultaneously coexist within the same frequency band.

Thus, in future networks, such as in “5G” networks, multi-modemulticarrier configuration is envisioned to meet the varying QoSrequirements of different applications and services. New numerologyproposed herein, which can support different subcarrier spacings (or,correspondingly, different OFDM symbol sizes) and the numerology isbeing defined in a way such that different OFDM symbol lengths fittogether very well, so as to facilitate inter-operability of differentOFDM configurations.

FIG. 4 illustrates two cases of multi-mode configurations, as anon-limiting example. Here, micro-subframes are defined—eachmicro-subframe can be equal to a few OFDM symbols. As an example, onemicro-subframe 410 in FIG. 4 is shown to consist of four “long” OFDMsymbols 412, 414, 416 and 418. (Each symbol in the illustration includesa cyclic prefix.) It should be noted here that the new numerology allowsinter-operability of different multicarrier modulation modes,characterized by different sub-carrier spacings and/or different symbollengths. In the example illustrated in FIG. 4, one micro-subframe 410with narrow subcarrier spacing and correspondingly long OFDM symbols412, 414, 416, and 418, is equal to four micro-subframes 420 with widesubcarrier spacing and correspondingly short OFDM symbols 422, 424, 426,etc.

It should be noted that while FIG. 4 illustrates examples where twomulticarrier modulation modes are used, more than two modes can also besupported in a mixed mode OFDM framework. Those familiar with thedetails of OFDM modulators and demodulators will appreciate that themode selection, i.e., the selection of the OFDM symbol length and thesub-carrier spacing for a given multicarrier modulation mode, can beachieved by appropriate selection of the FFT/iFFT size used to modulateand demodulate the signal, in combination with a given sample rate. InLTE, the subcarrier spacing is fixed at 15 kHz, and the symbol durationis set so that either 7 symbols (“normal” cyclic prefix) or 6 symbols(extended cyclic prefix) fit within a 500 microsecond slot. With theapproach described here, a multicarrier modulation mode like (if notidentical to) the OFDM modulation used in LTE can be used in the samefrequency band, and at the same time, as one or more other multicarriermodulation modes having, for example, wider subcarrier spacings andshorter symbol lengths.

One of the issues with the existing LTE standard is that it uses a fixedlarge-sized subframe structure, which results in resource wastage forvery small-sized data as is often the case in critical MTC (C-MTC)scenarios. Moreover, due to relatively coarse time granularity, the LTEresource blocks simply do not meet the very low latency requirements ofC-MTC applications. A second issue with the existing LTE standard isthat all the different services are bound to using the same subframestructure; the subframe cannot be split among different users in orderto support any emerging time-critical data services for C-MTCapplications.

Both of these issues are addressed by the multi-mode techniques detailedherein. C-MTC applications can be serviced with, for example, amulticarrier modulation mode having a relatively wide subcarrier spacingand relatively short OFDM symbol lengths, e.g., as compared to thoseused in LTE. This, in turn, facilitates communication with theseapplications using relatively shorter micro-subframes, such as themicro-subframes 420 shown in FIG. 4.

Described herein are apparatuses and methods for selecting and(re)configuring subcarrier spacing based on the required QoS metrics.These include, for example, a system that adapts selection of themulticarrier modulation mode (e.g., subcarrier spacing andmicro-subframe duration) based on the quality of service requirements,while allowing different sub-frames to coexist in the mixed-modemulticarrier setup. Such a system further allows the possibility ofreallocation of resources in the event of emergent time-critical trafficor other quickly changed QoS demands.

It should be understood that Orthogonal Frequency-Division Multiplexing(OFDM) is but one example of a multicarrier modulation technique. Otherexamples include discrete-Fourier-transform-spread (DFT-spread or DFTS-)OFDM, which is also referred to as single-carrier frequency-divisionmultiple access (SC-FDMA) or precoded OFDM. Still other examples includefilter-bank multicarrier (FBMC) modulation, pre-coded FBMC, andGeneralized Frequency-Division Multiplexing (GFDM). Those familiar withthese techniques will recognize that the digital signal processing foreach of these techniques will vary, but should appreciate that any oneor more of these multicarrier modulation techniques may be employed inthe multi-mode schemes detailed herein—accordingly, where exampleembodiments are described herein in terms of OFDM, the describedtechniques and apparatus may employ one or more other multicarriermodulation techniques in addition to or instead of OFDM.

FIG. 5 illustrates a diagram of a network access node 30, such as a basestation, according to some embodiments. The network node 30 facilitatescommunication between wireless devices and the core network. The networkaccess node 30 includes a communication interface circuit 38 includescircuitry for communicating with other nodes in the core network, radionodes, and/or other types of nodes in the network for the purposes ofproviding data and cellular communication services. The network accessnode 30 communicates with wireless devices via antennas 34 and atransceiver circuit 36. The transceiver circuit 36 may includetransmitter circuits, receiver circuits, and associated control circuitsthat are collectively configured to transmit and receive signalsaccording to a radio access technology, for the purposes of providingcellular communication services.

The network access node 30 also includes one or more processing circuits32 that are operatively associated with the communication interfacecircuit 38 or transceiver circuit 36. The network access node 30 usesthe communication interface circuit 38 to communicate with network nodesand the transceiver 36 to communicate with user equipments. For ease ofdiscussion, the one or more processing circuits 32 are referred tohereafter as “the processing circuit 32.” The processing circuit 32comprises one or more digital processors 42, e.g., one or moremicroprocessors, microcontrollers, Digital Signal Processors or DSPs,Field Programmable Gate Arrays or FPGAs, Complex Programmable LogicDevices or CPLDs, Application Specific Integrated Circuits or ASICs, orany mix thereof. More generally, the processing circuit 32 may comprisefixed circuitry, or programmable circuitry that is specially configuredvia the execution of program instructions implementing the functionalitytaught herein, or may comprise some mix of fixed and programmedcircuitry. The processor 42 may be multi-core, i.e., having two or moreprocessor cores utilized for enhanced performance, reduced powerconsumption, and more efficient simultaneous processing of multipletasks.

The processing circuit 32 also includes a memory 44. The memory 44, insome embodiments, stores one or more computer programs 46 and,optionally, configuration data 48. The memory 44 provides non-transitorystorage for the computer program 46 and it may comprise one or moretypes of computer-readable media, such as disk storage, solid-statememory storage, or any mix thereof. By way of non-limiting example, thememory 44 comprises any one or more of SRAM, DRAM, EEPROM, and FLASHmemory, which may be in the processing circuit 32 and/or separate fromthe processing circuit 32.

In general, the memory 44 comprises one or more types ofcomputer-readable storage media providing non-transitory storage of thecomputer program 46 and any configuration data 48 used by the networkaccess node 30. Here, “non-transitory” means permanent, semi-permanent,or at least temporarily persistent storage and encompasses bothlong-term storage in non-volatile memory and storage in working memory,e.g., for program execution.

Processing circuitry 32, whether alone or in combination with otherdigital hardware, is configured to perform one or more multicarriermodulation techniques (for network access node 30 acting as atransmitter node) and/or one or more multicarrier demodulationtechniques (for network access node 30 acting as a receiver node). Anexample modulation technique is shown in FIG. 6.

FIG. 6 illustrates OFDM modulation using an Inverse Fast FourierTransform (IFFT) or, more generally, and Inverse Discrete FourierTransform (IDFT). As will be explained in further detail below, two ormore simultaneous instantiations of the signal processing configurationshown in FIG. 6 can be used for multi-mode operation. As indicated bythe diagrams of FIG. 4, the number of OFDM subcarriers Nc and thesubcarrier spacing can vary. The number of subcarriers Nc can range fromfewer than a hundred to several thousand, depending on the subcarrierspacing that is selected and the overall transmission bandwidth.

As illustrated by FIG. 6, during each OFDM time interval with period T,Nc modulated symbols a0 to aNc-1 are provided to the size-N IDFT 604 bythe serial to parallel converter 602. The IFFT size corresponds to thetotal number of subcarriers that may be generated; the actual number ofgenerated subcarriers is Nc in FIG. 6.

The parallel output of IDFT 604 is converted to a serial time sequenceby parallel to serial converter 606. Cyclic prefix inserter 608 insertsa copy of part of the OFDM symbol at the beginning of the OFDM symbol,to make the OFDM signal less sensitive to time dispersion. Following thedigital to analog conversion by converter 610, the final output signalx(t) is then prepared for transmission.

FIG. 7 illustrates demodulation using FFT processing or, more generally,DFT processing. The received signal r(t) is sampled, and has its cyclicprefix removed by CP remover 702. The serial to parallel converter 704provides the samples of the OFDM symbol to the size-N DFT 706, whichextracts the data symbol values from the multiple subcarriers of themodulated signal. These data symbols are then converted to a serialstream of data symbols by parallel-to-serial converter 708. These datasymbols are then individually demodulated and the resulting data isdecoded.

FIG. 8 illustrates OFDM modulation with DFT-based precoding, orDFT-Spread OFDM (DFTS-OFDM), which can be referred to as single-carrierfrequency division multiple access (SC-FDMA). A block of M modulationsymbols is applied to Size-M DFT 802. The output of the DFT 802 is thenapplied to inputs of an OFDM modulator 804 that is implemented as asize-N IDFT; each input of the OFDM modulator 804 corresponds to asubcarrier of the resulting modulated signal. After conversion of theIDFT output to a time sequence in OFDM modulator 804, cyclic prefixinserter 806 inserts a cyclic prefix. Finally, output signal x(t) isoutput following conversion by digital-to-analog converter 808.

FIG. 9 illustrates DFTS-OFDM demodulation where a received signal r(t)is processed by cyclic prefix remover 902, Size-N DFT 904 and Size-MIDFT 906. It will be appreciated that the DFTS-OFDM demodulator shown inFIG. 9 is similar to the OFDM demodulator of FIG. 7, but with the size-MIDFT 906 added.

As previously mentioned, although OFDM and DFTS-OFDM are described asexample multicarrier modulation/demodulation techniques, the embodimentsof the present invention are not limited to such techniques. Also, it isnoted that any equalization (which may be done in the frequency domain,for example) is omitted from the figures for simplicity.

The IFFT size can be selected for modulation schemes with differentnumerologies, or variants of transmission parameters. The resultingallocations can provide for symbols with different subcarrier spacingsin different frequency band portions of the same time interval. Forexample, FIG. 10 shows two simultaneously applied multicarriermodulators 1002 and 1004. Modulator 1002 operates with an IFFT size of2048, and is capable of outputting 2048 relatively narrow modulatedsubcarriers, while modulator 1004 operates with an IFFT size of 512.Modulator 1004 produces up to 512 subcarriers that are four times aswide as those from modulator 1002, while also producing symbols that areone-fourth as length.

In the illustrated example, subcarriers 400-1000 of modulator 1002 aregenerated, each having a bandwidth of 16.875 kHz, while the subcarriers280-400 from modulator 1004 each have a bandwidth of 67.5 kHz. It willbe appreciated that the ranges of inputs used in modulators 1002 and1004 are selected so that the resulting subcarriers do not land on eachother. In the illustrated example, the 121 relatively wide subcarriersfrom modulator 1004 correspond to the portion of the spectrum that wouldbe occupied by subcarriers 1120-1600 of modulator 1002. Thecorresponding inputs of modulator are thus not used. This provides asmall gap, in the frequency domain, between the outputs from the twomulticarrier modulators, which means that the two modulated signals cansimply be added to one another, in the time domain, before transmission.The result is that in a given time interval, modulation scheme 1002provides longer blocks of symbols for a first non-overlapping portion ofthe frequency band, while modulation scheme 1004 provides shorter blocksof symbols in a greater number of spacings in a second non-overlappingportion of the frequency band. As a result, symbols can be directed todifferent receiver nodes using different subcarrier spacings, all withinthe same time interval.

Embodiments of the present invention provide for the use of differentmulticarrier modulation schemes for different portions of the frequencyband. Multicarrier modulation schemes may be different in that themodulation schemes may use different underlying techniques, or may usedifferent numerology/subcarrier spacing, or a combination of both. Forexample, one modulation scheme may use OFDM, while another, differing,modulation scheme may use DFTS-OFDM or FBMC. Similarly, two differingmulticarrier schemes may both use OFDM, but with different subcarrierspacings.

Further, the portions of the frequency band that are allocated to anygiven multicarrier modulation scheme may be dynamically changed, fromone time interval to the next. This means that the subcarrier spacingand symbol durations can differ in different portions of the frequencyband. While two multicarrier modulation schemes are combined in theexample shown in FIG. 10, it will be appreciated that this can beextended to three, four, or more multicarrier modulation schemes, solong as non-colliding portions of the frequency band are allocated tothe multiple modulators.

The different subcarrier spacings and symbol spacings for differentportions of the frequency band can be determined from one time intervalto the next based on service requirements, such as QoS requirements. Thetime interval can utilize various modulation schemes for variousportions of the time intervals to better maximize the usage of thebandwidth while satisfying the service requirements of various devicesor services.

According to various embodiments described herein, a transmitter and/ora receiver can perform communications using the multicarrier modulationand demodulation techniques described in FIGS. 6-10, or othermulticarrier modulation techniques, while accounting for varying servicerequirements. The transmitter and/or receiver may be a network accessnode (e.g., base station) or a wireless device (e.g., UE). For example,the processor 42 of the processing circuit 32 of network access node 30may execute a computer program 46 stored in the memory 44 thatconfigures the processor 42 to operate the network access node 30 as atransmitter node that performs multicarrier modulation. Processingcircuit 32 may comprise specialized digital hardware for performingDFT/IDFT processing, in cooperation with one or more program-basedprocessors, in some embodiments. The processor 42 is configured to, fora first time interval, allocate first and second non-overlappingportions of a frequency band to first and second multicarrier modulationschemes, respectively. The first and second multicarrier modulationschemes have first and second subcarrier spacings, respectively, and thefirst and second subcarrier spacings differ from one another. Theprocessor 42 is also configured to transmit, using transceiver circuit36, data to one or more wireless devices in the first time interval,using the first and second multicarrier modulation schemes in the firstand second portions of the frequency band.

The processor 42 is also configured to, for a second time interval,allocate third and fourth non-overlapping portions of a frequency bandto third and fourth multicarrier modulation schemes, respectively. Thethird and fourth multicarrier modulation schemes have third and fourthsubcarrier spacings, respectively, and the third and fourth subcarrierspacings differ from one another. The third and fourth portions differfrom the first and second portions or the third and fourth multicarriermodulation schemes differ from the first and second multicarriermodulation schemes, or both. To be clear, if both, this means that thethird and fourth portions differ from the first and second portions andthe third and fourth multicarrier modulation schemes differ from thefirst and second multicarrier modulation schemes. The processor 42 isalso configured to transmit data, using transceiver circuit 36, to oneor more wireless devices in the second time interval, using the thirdand fourth multicarrier modulation schemes in the third and fourthportions of the frequency band. This structure and functionality may bereferred to as modulation/demodulation circuitry 40 in the processingcircuit 32.

In stating that the third and fourth portions or modulation schemesdiffer from the first and second portions or modulation schemes, it isnot necessary that the third and fourth portions or modulation schemesboth be different than both the first and second portions or modulationschemes. In some cases, the third portion or modulation scheme can bethe same as the first portion or modulation scheme, it is just that thefourth portion or modulation scheme differs from the second portion ormodulation scheme. Likewise, the second and fourth portions ormodulation schemes can be the same, while the first and third portionsor modulation schemes are different. Of course, in some cases, all fourportions or modulations schemes can be completely different from each ofthe other portions or modulations schemes. It is noted that thereferences herein to first, second, third and fourth portions ormodulations schemes are used for explanatory purposes and do not limitthe embodiments to only two portions or modulation schemes in each timeinterval.

An example of the third and fourth portions differing from the first andsecond portions can include an instance where the first portion of thefrequency band is larger than the second portion in the first timeinterval, but the fourth portion is larger than the third portion in thesecond time interval. In another non-limiting example, the third andfourth portions differ from the first and second portions because thefirst and third portions are the same, but the fourth portion is largerthan the third and second portions, such as in FIG. 15, which is anexample signal diagram of mixed mode OFDM for consecutive timeintervals. In still another example, the sizes of the two portions inthe first time interval may be the same as the respective sizes of thetwo portions in the second time interval, but the locations within thefrequency band of one or both of the portions may vary from one timeinterval to the next.

An example of the third and fourth modulation schemes differing from thefirst and second modulation schemes can include where the underlyinginterference schemes differ. For instance, this may be where the firstand second modulation schemes of the first time interval and the thirdmodulation scheme of the second interval are, for example, OFDM whilethe fourth modulation scheme is, for example, DFTS-OFDM.

In another example, the modulation schemes may differ in subcarrierspacing. For example, the first modulation scheme may have a greaternumber of smaller subcarrier spacings than the second modulation schemein the first interval, while the fourth modulation scheme may have agreater number of smaller subcarrier spacings than the third modulationscheme in the second interval. In another non-limiting example, thethird and fourth modulation schemes may differ from the first and secondmodulation schemes when the second modulation scheme has a greaternumber of smaller subcarrier spacings than the first modulation scheme,while the third and fourth modulation schemes have the same number ofsubcarrier spacings as the first modulation but a different number thanthe second modulation scheme, such as in FIG. 15.

In some embodiments, the processing circuit 32 is configured to performa method for multicarrier modulation, such as method 1100. For example,FIG. 11 illustrates a method 1100 that includes, for a first timeinterval, allocating first and second non-overlapping portions of afrequency band to first and second multicarrier modulation schemes,respectively (block 1102). The first and second multicarrier modulationschemes have first and second subcarrier spacings, respectively, and thefirst and second subcarrier spacings differ from one another. The methodmay include transmitting data to one or more wireless devices in thefirst time interval, using the first and second multicarrier modulationschemes in the first and second portions of the frequency band (block1104). The method further includes, for a second time interval,allocating third and fourth non-overlapping portions of a frequency bandto third and fourth multicarrier modulation schemes, respectively (block1106). The third and fourth multicarrier modulation schemes have thirdand fourth subcarrier spacings, respectively, and the third and fourthsubcarrier spacings differ from one another. The third and fourthportions differ from the first and second portions or the third andfourth multicarrier modulation schemes differ from the first and secondmulticarrier modulation schemes, or both. The method may includetransmitting data to one or more wireless devices in the second timeinterval, using the third and fourth multicarrier modulation schemes inthe third and fourth portions of the frequency band (block 1108). It isnoted that this operation may continue for later time intervals, whetherthey are consecutive or not.

In some cases, a first or second time interval is dependent on thenumber of modulation symbols used, according to a multicarriermodulation scheme, for the first, second, third or fourth subcarrierspacing. In some cases, the length of the first or second time intervaldefines a point in time for allocation of the first, second, third andfourth portions of the frequency band and/or the respective subcarrierspacings.

The processor 42 of the processing circuit 32 may execute a computerprogram 46 stored in the memory 44 that configures the processor 42 tooperate the network access node as a receiver that performs multicarrierdemodulation. The processor 42 is thus configured to, in a first timeinterval, receive and demodulate data from a first portion of afrequency band, using a first multicarrier modulating scheme having afirst subcarrier spacing. The processor 42 is also configured to, in asecond time interval, receive and demodulate data from a second portionof the frequency band, using a second multicarrier modulating schemehaving a second subcarrier spacing. The first subcarrier spacing differsfrom the second subcarrier spacing. This structure and functionality mayalso be referred to as or be a part of modulation/demodulation circuitry40 in the processing circuit 32.

In some embodiments, the processing circuit 32 is configured to performa method for multicarrier demodulation, such as method 1200. Forexample, FIG. 12 illustrates a method 1200 that includes, in a firsttime interval, receiving and demodulating data from a first portion of afrequency band, using a first multicarrier modulating scheme having afirst subcarrier spacing (block 1202). The method 1200 further includes,in a second time interval, receiving and demodulating data from a secondportion of the frequency band, using a second multicarrier modulatingscheme having a second subcarrier spacing (block 1204). The firstsubcarrier spacing differs from the second subcarrier spacing.

The network access node 30 may be referred to as a node, network node ora radio network node. Network access node 30 can be any kind of networkaccess node that may include a base station, radio base station, basetransceiver station, evolved Node B (eNodeB), Node B, relay node, accesspoint, wireless access point, radio access point, UltraDense Network(UDN)/Software Defined Network (SDN) radio access node, Remote RadioUnit (RRU), Remote Radio Head (RRH), etc.

FIG. 13 illustrates a diagram of a wireless device, such as a userequipment 50, according to some embodiments. To ease explanation, theuser equipment 50 may also be considered to represent any wirelessdevices that may operate in a network. The UE 50 herein can be any typeof wireless device capable of communicating with network node or anotherUE over radio signals. The UE 50 may also be radio communication device,target device, device to device (D2D) UE, machine type UE or UE capableof machine to machine communication (M2M), a sensor equipped with UE,PDA (personal digital assistant), Tablet, mobile terminals, smart phone,laptop embedded equipped (LEE), laptop mounted equipment (LME), USBdongles, Customer Premises Equipment (CPE), etc.

The UE 50 communicates with a radio node or base station, such asnetwork access node 30, via antennas 54 and a transceiver circuit 56.The transceiver circuit 56 may include transmitter circuits, receivercircuits, and associated control circuits that are collectivelyconfigured to transmit and receive signals according to a radio accesstechnology, for the purposes of providing cellular communicationservices.

The UE 50 also includes one or more processing circuits 52 that areoperatively associated with the radio transceiver circuit 56. Theprocessing circuit 52 comprises one or more digital processing circuits,e.g., one or more microprocessors, microcontrollers, Digital SignalProcessors or DSPs, Field Programmable Gate Arrays or FPGAs, ComplexProgrammable Logic Devices or CPLDs, Application Specific IntegratedCircuits or ASICs, or any mix thereof. More generally, the processingcircuit 52 may comprise fixed circuitry, or programmable circuitry thatis specially adapted via the execution of program instructionsimplementing the functionality taught herein, or may comprise some mixof fixed and programmed circuitry. The processing circuit 52 may bemulti-core.

The processing circuit 52 also includes a memory 64. The memory 64, insome embodiments, stores one or more computer programs 66 and,optionally, configuration data 68. The memory 64 provides non-transitorystorage for the computer program 66 and it may comprise one or moretypes of computer-readable media, such as disk storage, solid-statememory storage, or any mix thereof. By way of non-limiting example, thememory 64 comprises any one or more of SRAM, DRAM, EEPROM, and FLASHmemory, which may be in the processing circuit 52 and/or separate fromprocessing circuit 52. In general, the memory 64 comprises one or moretypes of computer-readable storage media providing non-transitorystorage of the computer program 66 and any configuration data 68 used bythe user equipment 50.

The UE 50, whether or not part of modulation/demodulation circuitry 60,may be configured to perform at least the modulation and demodulationtechniques illustrated in FIGS. 4-12. For example, the processor 62 ofthe processor circuit 52 may execute a computer program 66 stored in thememory 64 that configures the processor 62 to operate as a transmitter,as explained above for processor 42 of the network access node 30. Thisfunctionality may be performed by modulation/demodulation circuitry 60in processing circuit 52. The processing circuit 52 of the UE 50 isconfigured to perform a method for multicarrier modulation, such asmethod 1100 of FIG. 11.

The processor 62 of the processor circuit 52 may execute a computerprogram 66 stored in the memory 64 that configures the processor 62 tooperate the user equipment node 50 as a receiver, as explained above forprocessor 42 of the network access node 30. This functionality may beperformed by modulation/demodulation circuitry 60 in processing circuit52. The processing circuit 52 of the UE 50 is also configured to performa method for multicarrier demodulation, such as method 1200 of FIG. 12.

In some cases, a transmitter node, such as network access node 30, maybe configured to operate with both such modulation and demodulationtechniques, while a receiver node, such as UE 50, is merely able toreceive and demodulate the symbols intended for it.

In some embodiments, the processing circuitry 40, 60 is configured toevaluate service requirements corresponding to data to be transmitted towireless devices in two different, perhaps consecutive, time intervals.Based on the evaluation, first and second portions of a frequency bandcan be allocated to first and second multicarrier modulation schemes fora first time interval, while third and fourth portions of a time thefrequency band are allocated to third and fourth multicarrier modulationschemes for a second time interval. In some cases, service requirementsfor the wireless devices can be received prior to the evaluation of theservice requirements.

The device capabilities of the wireless devices can also affect theallocations. Such device capabilities may include information regardingthe capability of respective wireless devices to receive and demodulatethe symbols placed in time intervals, where the subcarrier spacings mayvary from time interval to time interval. For example, device capabilityinformation may indicate that a first wireless device can operate usingonly a using only a single multicarrier modulation scheme. Therefore, atleast one portion of the frequency band in the first and/or second timeinterval is allocated to the single multicarrier modulation scheme inresponse to said indication. It may follow that different modulationschemes may be used for different devices within the same time intervaland/or over multiple consecutive time intervals.

In some embodiments, the network access node 30 and/or the UE 50 areconfigured to operate in a dedicated mode of operation with fixedservice requirement, such as a QoS requirement. In this case, a terminaldevice (UE) operates in a particular dedicated (pre-coded) multicarriermode. Note that (pre-coded) multicarrier could be (but not limited to)OFDM, FBMC, DFT-spread OFDM (DFTS-OFDM), pre-coded FBMC and generalizedfrequency-division multiplexing (GFDM). Of course, this case does notrestrict its interoperability with other devices using different(dedicated or mixed) multicarrier modes. As a non-limiting example,consider a simple illustration with only two multicarrier modes as shownin FIG. 14. UE1 supports only mobile broadband (MBB) traffic with longsymbols and UE2 supports only C-MTC traffic with short symbols. Bothkinds of devices are being served by a single base station (BS)supporting mixed mode multicarrier. However, different frequencysub-bands are used by different multicarrier modes. Multicarrierconfiguration of a UE can be passed on to the corresponding networkaccess node 30, or BS, via control signaling at the time when the UEconnects to the network. The multicarrier configuration for a particularUE will remain the same as long as the UE is connected to the network oras long as the QoS needs are not changed.

In other embodiments, the network access node 30 and/or the UE 50 may beconfigured to support a mixed mode of multicarrier operation with avariable service requirement, such as a variable QoS requirement. FIG.15 shows the case when UE 2 operates on different multicarrier modesbased on the QoS requirements. This case can be considered a moregeneric case for a terminal device (or UE) with multiple serviceclasses. Corresponding to the service class, an appropriate multicarriermode is selected. As a non-limiting example, consider mixed multicarriermode of two for simplicity. In order to support both C-MTC and MBB typeof traffic, the device itself or BS selects the short symbol for C-MTCtraffic to adhere to strict timeliness requirements while it uses longsymbols for MBB (or other non-critical) traffic.

Control signaling can occur between the UE and the BS using a defaultmulticarrier configuration (for example, multicarrier mode with smallestsymbol size). A UE (or BS) can select the multicarrier configurationbased on the traffic QoS requirement and signal the BS (or device) inPUCCH (or PDCCH) or other similar control channels (using a defaultconfiguration), about the selected multicarrier configuration. Forexample, depending upon the total number of supported multicarrieroptions in the mixed mode operation, a few bits can be reserved in SR orPDCCH to indicate the selected multicarrier mode.

In some embodiments, no mode is selected, as in the case of ControlChannel Usage. For emergency C-MTC services like alarm signals orcommand messages with data size is smaller than a certain threshold, amodulation technique may make use of the PUCCH itself to transmit data.The BS in this case will not explicitly allocate any resources. Thecontrol signal will use the default multicarrier mode so that the BS andthe UE do not have to exchange any control overhead in order to agree onthe multicarrier mode. Alternatively, PUCCH can be configured with oneof the available multicarrier numerologies, e.g., the short symbolnumerology due to strict latency requirements.

In some embodiments, a scheme for the reallocation of an alreadyallocated resource is described in the case when a real-time datatraffic requirement emerges and there is no free resource available. TheBS accommodates the emerged real-time traffic in place of an alreadyallocated resource with less latency critical demands. Obviously, theless time-critical service is reallocated to other resources availablein the system.

The reallocation process could involve a new multicarrier configurationbased on the service class. A non-limiting illustration of this processis shown in FIG. 16. It can be noted from the top of FIG. 16 that allthe system resources are occupied at the time instant when the trafficfrom UE3 and UE7 with strict timeliness requirements emerges. Whiledelaying UE3 and UE7 resource allocation to a potentially futuremicro-subframe would not meet the QoS demands, an already allocatedresource to UE1 and UE2 can be made available since UE1 and UE2 do nothave time-critical traffic QoS requirements. The process of allocatingresources to UE3 and UE7 and reallocating resources to UE1 and UE2 isillustrated in FIG. 16 at the bottom. It is worth noticing that whilereallocating the resource to UE3 and UE7, the OFDM configuration is alsochanged appropriately.

In some embodiments, critical data can be prioritized per micro-subframeof the OFDM mode with a widest available subcarrier. FIG. 17 showsprioritization of critical data. If frequency-division duplex (FDD)duplexing is supported on a device terminal or UE, the UE must listen todownlink assignments on the smallest possible micro-subframe level whilecarrying out transmission. In this way, if the critical data arrives,there is a possibility of taking resources (time and/or frequency) fromUE with non-critical service. This requires extra signaling to the UEwith non-critical data to halt its transmission.

FIG. 18 illustrates an example functional module or circuit architectureas may be implemented in the network access node 30 operating as atransmitter node, e.g., based on the modulation/demodulation circuitry40. The illustrated embodiment at least functionally includes anallocating module 1802 for, a first time interval, allocating first andsecond non-overlapping portions of a frequency band to first and secondmulticarrier modulation schemes, respectively. The first and secondmulticarrier modulation schemes have first and second subcarrierspacings, respectively, and the first and second subcarrier spacingsdiffer from one another. The embodiment also includes a transmittingmodule 1804 for transmitting data to one or more wireless devices in thefirst time interval, using the first and second multicarrier modulationschemes in the first and second portions of the frequency band. Theallocation module 1802 is also configured, for a second time interval,for allocating third and fourth non-overlapping portions of a frequencyband to third and fourth multicarrier modulation schemes, respectively.The third and fourth multicarrier modulation schemes have third andfourth subcarrier spacings, respectively, and the third and fourthsubcarrier spacings differ from one another. The third and fourthportions differ from the first and second portions or the third andfourth multicarrier modulation schemes differ from the first and secondmulticarrier modulation schemes, or both. The transmitting module 1804is also configured for transmitting data to one or more wireless devicesin the second time interval, using the third and fourth multicarriermodulation schemes in the third and fourth portions of the frequencyband.

FIG. 19 illustrates an example functional module or circuit architectureas may be implemented in the network access node 30 operating as areceiver node, e.g., based on the modulation/demodulation circuitry 40.The illustrated embodiment at least functionally includes a receivingand demodulating nodule 1902 for, in a first time interval, receivingand demodulating data from a first portion of a frequency band, using afirst multicarrier modulating scheme having a first subcarrier spacing.The receiving and demodulating module 1902 is also configured for, in asecond time interval, receiving and demodulating data from a secondportion of the frequency band, using a second multicarrier modulatingscheme having a second subcarrier spacing. The first subcarrier spacingdiffers from the second subcarrier spacing.

FIG. 20 illustrates an example functional module or circuit architectureas may be implemented in the user equipment node 50 operating as atransmitter node, e.g., based on the modulation/demodulation circuitry60. The illustrated embodiment at least functionally includes anallocating module 2002, for a first time interval, for allocating firstand second non-overlapping portions of a frequency band to first andsecond multicarrier modulation schemes, respectively. The first andsecond multicarrier modulation schemes have first and second subcarrierspacings, respectively, and the first and second subcarrier spacingsdiffer from one another. The embodiment also includes a transmittingmodule 2004 for transmitting data to one or more wireless devices in thefirst time interval, using the first and second multicarrier modulationschemes in the first and second portions of the frequency band. Theallocating module 2002 is also configured, for a second time interval,for allocating third and fourth non-overlapping portions of a frequencyband to third and fourth multicarrier modulation schemes, respectively.The third and fourth multicarrier modulation schemes have third andfourth subcarrier spacings, respectively, and the third and fourthsubcarrier spacings differ from one another. The third and fourthportions differ from the first and second portions or the third andfourth multicarrier modulation schemes differ from the first and secondmulticarrier modulation schemes, or both. The transmitting module 2004is also configured for transmitting data to one or more wireless devicesin the second time interval, using the third and fourth multicarriermodulation schemes in the third and fourth portions of the frequencyband.

FIG. 21 illustrates an example functional module or circuit architectureas may be implemented in the user equipment node 50 operating as areceiver node, e.g., based on the modulation/demodulation circuitry 60.The illustrated embodiment at least functionally includes a receivingand demodulating module 2102 for, in a first time interval, receivingand demodulating data from a first portion of a frequency band, using afirst multicarrier modulating scheme having a first subcarrier spacing.The receiving and demodulating module 2104 is also configured for, in asecond time interval, receiving and demodulating data from a secondportion of the frequency band, using a second multicarrier modulatingscheme having a second subcarrier spacing. The first subcarrier spacingdiffers from the second subcarrier spacing.

The embodiments described herein provide a number of advantages. Forexample, advantages include higher performance through more granulardynamic resource management. The embodiments allow a system to fulfill awide range of QoS requirements. Advantages also include allowing theefficient management of resources among devices supporting mixed modemulticarrier operation with varying degree of application traffic QoSdemands. The system is also allowed to reallocate resources in ordermeet the strict timeliness requirements of emerging unpredictabletraffic. Having the capability to reallocate resources at runtimeenables handling of alarms in C-MTC use cases and dealing with dynamicrequirements.

Advantages also include enabling a system to achieve efficientcoexistence of devices having dedicated capabilities (also different butfixed capabilities) with devices supporting mixed mode operation.Devices with a single (dedicated) mode of operation simplify thehardware and hence reduce the device cost. Moreover, this indirectlyhelps a system in lowering the power consumption budget. It is highlylikely that efficient coexistence and the management of devices withdifferent multicarrier modes is to be required.

Notably, modifications and other embodiments of the disclosedinvention(s) will come to mind to one skilled in the art having thebenefit of the teachings presented in the foregoing descriptions and theassociated drawings. Therefore, it is to be understood that theinvention(s) is/are not to be limited to the specific embodimentsdisclosed and that modifications and other embodiments are intended tobe included within the scope of this disclosure. Although specific termsmay be employed herein, they are used in a generic and descriptive senseonly and not for purposes of limitation.

What is claimed is:
 1. A method in a transceiver configured to transmitand receive wireless transmissions, the method comprising: in a firsttime interval, modulating and transmitting data on a first portion of afrequency band, using a first multicarrier modulation mode having afirst subcarrier spacing; and in a second time interval, modulating andtransmitting data on a second portion of the frequency band, using asecond multicarrier modulation mode having a second subcarrier spacing;wherein the first subcarrier spacing differs from the second subcarrierspacing; wherein the transceiver is comprised in a user equipment andwherein the method further comprises sending, to a radio base station,an indication of the user equipment's capabilities with respect tomulticarrier modulation modes.
 2. The method of claim 1, wherein thefirst portion of the frequency band is different from the second portionof the frequency band.
 3. The method of claim 1, wherein the first andsecond subcarrier spacings for the first and second portions of thefrequency band are based on different service requirements in said firstand second time interval.
 4. The method of claim 1, wherein the methodfurther comprises sending, to a radio base station, an indication ofservice requirements.
 5. The method of claim 1, wherein the methodfurther comprises receiving information about a selected multicarriermodulation mode on a control channel from a radio base station.
 6. Amethod in a transceiver configured to transmit and receive wirelesstransmissions, the method comprising: in a first time interval,modulating and transmitting data on a first portion of a frequency band,using a first multicarrier modulation mode having a first subcarrierspacing; and in a second time interval, modulating and transmitting dataon a second portion of the frequency band, using a second multicarriermodulation mode having a second subcarrier spacing; wherein the firstsubcarrier spacing differs from the second subcarrier spacing; whereinthe transceiver is comprised in a radio base station and wherein themethod further comprises receiving, from a user equipment, an indicationof said user equipment's capabilities with respect to multicarriermodulation modes.
 7. The method of claim 6, wherein the method furthercomprises receiving, from a user equipment, an indication of servicerequirement.
 8. The method of claim 6, wherein the method furthercomprises selecting a multicarrier modulation mode to be used based onservice requirements.
 9. The method of claim 6, wherein the methodfurther comprises signaling information about the selected multicarriermodulation mode on a control channel to a user equipment.
 10. A wirelesstransmitter, comprising: a transceiver circuit configured to transmitand receive wireless transmissions according to multicarrier modulationschemes; and a processing circuit operatively connected to thetransceiver circuit and configured to control the transceiver circuitto: in a first time interval, modulate and transmit data on a firstportion of a frequency band, using a first multicarrier modulation modehaving a first subcarrier spacing; and in a second time interval,modulate and transmit data on a second portion of the frequency band,using a second multicarrier modulation mode having a second subcarrierspacing; wherein the first subcarrier spacing differs from the secondsubcarrier spacing; wherein the transceiver is configured for operationin a user equipment and wherein the processing circuit is furtherconfigured to control the transceiver to send, to a radio base station,an indication of the user equipment's capabilities with respect tomulticarrier modulation modes.
 11. The wireless transmitter of claim 10,wherein the first portion of the frequency band is different from thesecond portion of the frequency band.
 12. The wireless transmitter ofclaim 10, wherein the first and second subcarrier spacings for the firstand second portions of the frequency band are based on different servicerequirements in said first and second time interval.
 13. The wirelesstransmitter of claim 10, wherein the processing circuit is furtherconfigured to control the transceiver to send, to a radio base station,an indication of service requirements.
 14. The wireless transmitter ofclaim 10, wherein the processing circuit is further configured tocontrol the transceiver to receive information about a selectedmulticarrier modulation mode on a control channel from a radio basestation.